Antenna



FIG. 1 is a perspective view of an antenna according to our design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a bottom view thereof;

FIG. 6 is a right side view thereof; and,

FIG. 7 is a left side view thereof.

The broken lines are for illustrative purposes only and form no part of the claimed design. The dot-dash line represents the boundary between claimed and unclaimed areas of the antenna. All claimed areas are flat and coplanar. 

The ornamental design for an antenna, as shown and described. 